The invention relates to an image reading apparatus that optically reads an original surface of a sheet, and to an image processing apparatus mounted with the image reading apparatus to form an image on a sheet based on image data from this image reading apparatus.
Higher image quality, greater multi-functionality and more compactness in the image reading apparatuses, image forming apparatuses and copiers have been made recently along with the sudden development of the electronic technologies and optical technologies.
An image reading apparatus uses CCD, which is an optical conversion means for converting an original image to electrical signals to precisely optically read an original surface and employs high resolution having a large numbers number of pixels. An image forming apparatus equipped with such image reading apparatus not only has a copying function, but also has a printer function to receive print data from data processing apparatuses, such as facsimile function and external personal computer, to print that data. Further, the image forming apparatus has a function to output image data acquired by an image reading apparatus to a data processing apparatus, such as a personal computer. A single unit image forming apparatus is provided with a plurality of functions in an effort to occupy less business space and to improve efficiency.
FIG. 8 shows an external view of an image forming apparatus 210 having such plural functions. Below an image reading apparatus housing 217 and above an image forming apparatus housing 218, a discharge tray 216 is disposed. The image forming apparatus 210 greatly reduces a substantial setup space because the discharge tray 216 for storing sheets formed with images thereon is disposed inside the housing without protruding to the outside of the image forming apparatus 210. Furthermore, the image reading apparatus described above that sets an original on a platen glass 162 which is mounted on the housing 161 as shown in FIG. 9 and that optically reads the original image to an image sensor 172, such as a CCD, by the cooperative operation of a first carriage 163 and a second carriage 167, is known.
To describe this image reading apparatus in further detail, an original placed on the platen glass 162 is illuminated by a light source 164 disposed in the first carriage 163. Light reflected from the original passes an aperture 165 in the first carriage 163 and the light path is deflected in the sub-scanning direction by a first mirror 166. The image on the original whose light path has been deflected is deflected downward by a second mirror 168 on the second carriage 167 and is then deflected in the direction of a lens 171 by a third mirror 169. The image collected in the lens 171 is converted to electrical signals by the CCD 172 mounted to a CCD substrate 173. Then, at the CCD 172, the image converted to electrical signals is processed by an image processing circuit on a control board (not shown in the drawings) disposed in the housing 161.
The structure is formed such that the light path passing via the three mirrors 166, 168 and 169 from the original surface to the lens 171 is always the same length and the first carriage 163 sub-scans at the speed V which is twice greater in speed than that of the second carriage 167.
In this way, because a plurality of cassettes for a variety of sheet sizes is stored in a stacked state in the image forming apparatus, it requires a space to remove the sheets on the discharge tray above the discharge tray, so that the image forming apparatus naturally becomes larger in the height direction. Also, as the image forming apparatus becomes larger in the height direction, the position for forming the image reading apparatus becomes higher to prevent easy handling of the original on the image reading apparatus.
An apparatus to solve such issue is disclosed in Japanese Patent Publication (KOKAI) No. 8-133554 which teaches forming a protrusion on a part of the bottom surface of the image reading apparatus, as shown in FIG. 10, and establishing a storage space for the discharge tray parallel to this protruding portion.
The structure disclosed in Japanese Patent Publication No. 8-133554 uses the protruding portion 301 on the bottom of the image reading apparatus 300 together with the interconnecting portion of the image forming apparatus 305 and by arranging electrical components 302 of the optical system in this protruding portion. Thus, it is possible to decrease the image reading apparatus 300 in the height direction. Furthermore, the entire apparatus including the image reading apparatus is made more compact because the space formed next to this protruding portion 301 is also used as the storage space 303 of the discharge tray 306.
However, in the apparatus disclosed in Japanese Patent Publication No. 8-133554, the protruding portion 301 and the discharge portion 307 are arranged side by side, so that enough storage space can not be formed (removal space). Thus, the removal of the sheet is not easy and there is a problem of not being able to visually confirm the sheet discharged to the discharge tray 306.
Furthermore, an original feeding mechanism 304 to automatically supply the originals stored on the discharge tray 306 to the top of the platen 309, is located above the storage space 303 on the discharge tray 306. A sufficiently strong frame for the entire image reading apparatus is essential to provide stable support for this original feeding mechanism. For that reason, as the image reading apparatus becomes heavier, it becomes, then, essential to increase the strength of the frame of the image forming apparatus to support this image reading apparatus thereby creating the problem of increasing the weight of the entire apparatus system including the image reading apparatus and the image forming apparatus.
Also, the handling of the originals and sheets is inconvenient because the setting direction of the originals supplied by the original feeding mechanism 304 and the direction of removal of the sheets with images thereupon are different.
An object of the present invention is to solve the above problems and to provide an image forming apparatus including an image reading apparatus, which improves the operability of setting an original and taking out a sheet having an image formed thereon, makes the height direction more compact, reduces the weight and has stability.
An image reading apparatus of the invention is designed to be disposed above an image forming apparatus to form a storage space with an upper surface of the image forming apparatus. The image reading apparatus includes a platen for reading an original; an original feeding mechanism to feed the original to one side of the platen and to discharge the same; reading means disposed under the platen and arranged such that the reading means is moved to read the original immovably placed on the platen and stopped at a predetermined position to read the original passing over the platen with the original feeding means; control means connected to the reading means to control a reading operation of the reading means; and a housing including a first bottom surface to form the storage space, and a second bottom surface protruding from the first bottom surface to be mounted to the image forming apparatus. The second bottom surface of the housing is formed at one side of the platen so that the control means and the original feeding mechanism are disposed above the second bottom surface.